Africa needs engineers, but its engineering students often end up working at auditing firms and banks. Why? Kamau Gachigi suspects its because they dont have the spaces and materials needed to test their ideas and start businesses. To solve this problem, Gachigi started Gearbox, a makerspace and hardware accelerator that provides a rapid prototyping environment for both professionals and people with no formal engineering background. In this forward-thinking talk, he shares some of the extraordinary projects and innovations coming out of his Kenyan fab lab.

Space physicist Miho Janvier studies solar storms: giant clouds of particles that escape from the Sun and can disrupt life on Earth (while also producing amazing auroras). How do you study the atmosphere on the Sun, which burns at temperatures of up to around 10 million degrees Kelvin? With math! Join the TED Fellow as she shares her work trying to better understand how the Sun affects us here on Earth.

Joan Blades and John Gable want you to make friends with people who vote differently than you do. A pair of political opposites, the two longtime pals know the value of engaging in honest conversations with people you dont immediately agree with. Join them as they explain how to bridge the gaps in understanding between people on opposite sides of the political spectrum -- and create opportunities for mutual listening and consideration (and, maybe, lasting friendships).

How will we live elsewhere in the galaxy? On Earth, natural resources for creating structures are abundant, but sending these materials up with us to the Moon or Mars is clunky and cost-prohibitive. Enter architect Xavier De Kestelier, who has a radical plan to use robots and space dust to 3D print our interplanetary homes. Learn more about the emerging field of space architecture with this fascinating talk about the (potentially) not-too-distant future.

Mumbai, Delhi, Chennai, Kolkata -- all the major cities across India have one great thing in common: they welcome people arriving in search of work. But what lies at the other end of such openness and acceptance? Sadly, a shortage of housing for an estimated 100 million people, many of whom end up living in informal settlements. Gautam Bhan, a human settlement expert and researcher, is boldly reimagining a solution to this problem. He shares a new vision of urban India where everyone has a safe, sturdy home. (In Hindi with English subtitles)

If youre undergoing surgery, you want the best surgical team to collaborate on your case, no matter where they are. Surgeon and entrepreneur Nadine Hachach-Haram is developing a new system that helps surgeons operate together and train one another on new techniques -- from remote locations using low-cost augmented reality tools. Watch the system in action as she joins a surgeon in Minnesota performing a knee surgery, live on her laptop from the TED stage in New Orleans. As Hachach-Haram says: "Through simple, everyday devices that we take for granted, we can really do miraculous things." (This talk contains graphic images of surgery.)

Theres something amazing growing in the city of Detroit: healthy, accessible, delicious, fresh food. In a spirited talk, fearless farmer Devita Davison explains how features of Detroits decay actually make it an ideal spot for urban agriculture. Join Davison for a walk through neighborhoods in transformation as she shares stories of opportunity and hope. "These arent plots of land where were just growing tomatoes and carrots," Davison says. "Were building social cohesion as well as providing healthy, fresh food."

Whats the secret to making content people love? Join BuzzFeeds Publisher Dao Nguyen for a glimpse at how her team creates their tempting quizzes, lists and videos -- and learn more about how theyve developed a system to understand how people use content to connect and create culture.

Whats the harm in buying a knock-off purse or a fake designer watch? According to counterfeit investigator Alastair Gray, fakes like these fund terrorism and organized crime. Learn more about the trillion-dollar underground economy of counterfeiting -- from the criminal organizations that run it to the child labor they use to produce its goods -- as well as measures you can take to help stop it. "Lets shine a light on the dark forces of counterfeiting that are hiding in plain sight," Gray says.

Look at the letters around you: on street signs, stores, restaurant menus, the covers of books. Whether you realize it or not, the letters are speaking to you, telling you something beyond the literal text -- that whatever they represent is modern or finely crafted or fantastical or zany. Learn to decode this secret language with lettering designer Martina Flor as she explains how altering the shapes, colors and textures of letters changes how we perceive them. (In Spanish with English subtitles)

Theres nothing quite like a good nights sleep. What if technology could help us get more out of it? Dan Gartenberg is working on tech that stimulates deep sleep, the most regenerative stage which (among other wonderful things) might help us consolidate our memories and form our personalities. Find out more about how playing sounds that mirror brain waves during this stage might lead to deeper sleep -- and its potential benefits on our health, memory and ability to learn.

Justin Baldoni wants to start a dialogue with men about redefining masculinity -- to figure out ways to be not just good men but good humans. In a warm, personal talk, he shares his effort to reconcile who he is with who the world tells him a man should be. And he has a challenge for men: "See if you can use the same qualities that you feel make you a man to go deeper," Baldoni says. "Your strength, your bravery, your toughness: Are you brave enough to be vulnerable? Are you strong enough to be sensitive? Are you confident enough to listen to the women in your life?"

Luvvie Ajayi isnt afraid to speak her mind or to be the one dissenting voice in a crowd, and neither should you. "Your silence serves no one," says the writer, activist and self-proclaimed professional troublemaker. In this bright, uplifting talk, Ajayi shares three questions to ask yourself if youre teetering on the edge of speaking up or quieting down -- and encourages all of us to get a little more comfortable with being uncomfortable.

Conventional wisdom says that to win an election, you need to play to your constituencies basest, most divisive instincts. But as a candidate for mayor of Tulsa, Oklahoma, G.T. Bynum decided to skip the smear campaigns, tell voters what he wanted to accomplish and give them ways to measure his success -- and it led him to win the election. In a hopeful, funny talk, Bynum shares how hes tackling his citys most pressing issues and says that we need to set aside philosophical disagreements and focus on the aspirations that unite us.

Educator and entrepreneur Sebastian Thrun wants us to use AI to free humanity of repetitive work and unleash our creativity. In an inspiring, informative conversation with TED Curator Chris Anderson, Thrun discusses the progress of deep learning, why we shouldnt fear runaway AI and how society will be better off if dull, tedious work is done with the help of machines. "Only one percent of interesting things have been invented yet," Thrun says. "I believe all of us are insanely creative ... [AI] will empower us to turn creativity into action."

Natsai Audrey Chieza is a designer on a mission -- to reduce pollution in the fashion industry while creating amazing new things to wear. In her lab, she noticed that the bacteria Streptomyces coelicolor makes a striking red-purple pigment, and now shes using it to develop bold, color-fast fabric dye that cuts down on water waste and chemical runoff, compared with traditional dyes. And she isnt alone in using synthetic biology to redefine our material future; think -- "leather" made from mushrooms and superstrong yarn made from spider-silk protein. Were not going to build the future with fossil fuels, Chieza says. Were going to build it with biology.

Fresh food free of chemicals and pesticides is hard to come by in China: in 2016, the Chinese government revealed half a million food safety violations in just nine months. In the absence of safe, sustainable food sources, TED Fellow Matilda Ho launched Chinas first online farmers market, instituting a zero-tolerance test towards pesticides, antibiotics and hormones in food. She shares how shes growing her platform from the ground up and bringing local, organically grown food to the families that need it.

Keller Rinaudo wants everyone on earth to have access to basic health care, no matter how hard it is to reach them. With his start-up Zipline, he has created the worlds first drone delivery system to operate at national scale, transporting blood and plasma to remote clinics in East Africa with a fleet of electric autonomous aircraft. Find out how Rinaudo and his team are working to transform health care logistics throughout the world -- and inspiring the next generation of engineers along the way.

What makes our bodies age ... our skin wrinkle, our hair turn white, our immune systems weaken? Biologist Elizabeth Blackburn shares a Nobel Prize for her work finding out the answer, with the discovery of telomerase: an enzyme that replenishes the caps at the end of chromosomes, which break down when cells divide. Learn more about Blackburns groundbreaking research -- including how we might have more control over aging than we think.

Leah Chases New Orleans restaurant Dooky Chase changed the course of American history over gumbo and fried chicken. During the civil rights movement, it was a place where white and black people came together, where activists planned protests and where the police entered but did not disturb -- and it continues to operate in the same spirit today. In conversation with TEDWomen Curator Pat Mitchell, the 94-year old Queen of Creole Cuisine (who still runs the Dooky Chase kitchen) shares her wisdom from a lifetime of activism, speaking up and cooking.

We all know that when we make decisions in groups, they dont always go right -- and sometimes they go very wrong. How can groups make good decisions? With his colleague Dan Ariely, neuroscientist Mariano Sigman has been inquiring into how we interact to reach decisions by performing experiments with live crowds around the world. In this fun, fact-filled explainer, he shares some intriguing results -- as well as some implications for how it might impact our political system. In a time when people seem to be more polarized than ever, Sigman says, better understanding how groups interact and reach conclusions might spark interesting new ways to construct a healthier democracy.

For the introverts among us, traditional forms activism like marches, protests and door-to-door canvassing can be intimidating and stressful. Take it from Sarah Corbett, a former professional campaigner and self-proclaimed introvert. She introduces us to "craftivism," a quieter form of activism that uses handicrafts as a way to get people to slow down and think deeply about the issues theyre facing, all while engaging the public more gently. Who says an embroidered handkerchief cant change the world?

The combined market capitalization of Amazon, Apple, Facebook and Google is now equivalent to the GDP of India. How did these four companies come to infiltrate our lives so completely? In a spectacular rant, Scott Galloway shares insights and eye-opening stats about their dominance and motivation -- and what happens when a society prizes shareholder value over everything else. Followed by a Q&A with TED Curator Chris Anderson. (Note: This talk contains graphic language.)

Niti Bhan studies business strategy for Africas informal markets: the small shops and stands, skilled craftspeople and laborers who are the invisible engine that keeps the continents economy running. Its tempting to think of these workers as tax-dodgers, even criminals -- but Bhan makes the case that this booming segment of the economy is legitimate and worthy of investment. "These are the fertile seeds of businesses and enterprises," Bhan says. "Can we start by recognizing these skills and occupations?"

The biggest obstacle to dealing with climate disruptions lies between your ears, says psychologist and economist Per Espen Stokes. Hes spent years studying the defenses we use to avoid thinking about the demise of our planet -- and figuring out a new way of talking about global warming that keeps us from shutting down. Step away from the doomsday narratives and learn how to make caring for the earth feel personable, do-able and empowering with this fun, informative talk.

Kayla Briët creates art that explores identity and self-discovery -- and the fear that her culture may someday be forgotten. She shares how she found her creative voice and reclaimed the stories of her Dutch-Indonesian, Chinese and Native American heritage by infusing them into film and music time capsules.

One in five women in the United States will not have a biological child, and Christen Reighter is one of them. From a young age, she knew she didnt want kids, in spite of the insistence of many people (including her doctor) who told her shed change her mind. In this powerful talk, she shares her story of seeking sterilization -- and makes the case that motherhood is an extension of womanhood, not the definition.

With warmth and grace, Beth Malone tells the deeply personal story of her dads struggle with frontotemporal lobe dementia, and how it changed how she thinks about death (and life). A moving talk about a daughters love -- and of letting go and finding peace.

Military leaders have known for millennia that the time to prepare for a challenge is before it hits you, says scientist and retired US Navy officer David Titley. He takes us from the humanitarian catastrophe in Syria to the icy shores of Svalbard to show how the military approaches the threat of climate change, in a refreshingly practical, nonpartisan take on climate preparedness. "The ice doesnt care whos in the White House. It doesnt care which party controls your congress. It doesnt care which party controls your parliament," Titley says. "It just melts."

What do you think would happen if you invited an individual with mental health issues who had been homeless for many years to move directly from the street into housing? Loyd Pendleton shares how he went from skeptic to believer in the Housing First approach to homelessness -- providing the displaced with short-term assistance to find permanent housing quickly and without conditions -- and how it led to a 91 percent reduction in chronic homelessness over a ten-year period in Utah.

Gender should be the least remarkable thing about someone, but transgender people are still too often misunderstood. To help those who are scared to ask questions or nervous about saying the wrong thing, Jackson Bird shares a few ways to think about trans issues. And in this funny, frank talk, he clears up a few misconceptions about pronouns, transitioning, bathrooms and more.

In 2011, Teresa Njoroge was convicted of a financial crime she didnt commit -- the result of a long string of false accusations, increasing bribe attempts and the corrupt justice system in her home in Kenya. Once incarcerated, she discovered that most of the women and girls locked up with her were also victims of the same broken system, caught in a revolving door of life in and out of prison due to poor education and lack of economic opportunity. Now free and cleared by the courts of appeal, Njoroge shares how shes giving women in prison the skills, tools and support they need to break the cycle of poverty and crime and build a better life.

In halls of justice around the world, how can we ensure everyone is treated with dignity and respect? A pioneering judge in New Jersey, Victoria Pratt shares her principles of "procedural justice" -- four simple, thoughtful steps that redefined the everyday business of her courtroom in Newark, changing lives along the way. "When the court behaves differently, naturally people respond differently," Pratt says. "We want people to enter our halls of justice ... and know that justice will be served there."

With fantastic new maps that show interactive, visual representations of urban fragility, Robert Muggah articulates an ancient but resurging idea: cities shouldnt just be the center of economics -- they should also be the foundation of our political lives. Looking around the world, from Syria to Singapore to Seoul and beyond, Muggah submits six principles for how we can build more resilient cities. "Cities are where the future happens first. Theyre open, creative, dynamic, democratic, cosmopolitan, sexy," Muggah says. "Theyre the perfect antidote to reactionary nationalism."

Sometimes trying your best isnt enough; when the situation demands it, you need to be perfect. For Jon Bowers, who runs a training facility for professional delivery drivers, the stakes are high -- 100 people in the US die every day in car accidents -- and its perfection, or "a willingness to do what is difficult to achieve what is right," that he looks to achieve. He explains why we should all be equally diligent about striving toward perfection in everything we do, even if it means failing along the way.

Ameenah Gurib-Fakim has been an academic, an entrepreneur and is now the president of Mauritius -- the first Muslim female head of state in Africa. In a wide-ranging conversation with journalist Stephanie Busari, Gurib-Fakim discusses the humble beginnings of her political career, what its like to be both a person of faith and a scientist and why we need to value traditional African knowledge, among much more. "I dont think you should take yourself seriously," she says. "You need to have trust in what you can do, have confidence in yourself and give yourself a set of goals and just work towards them."

Megafires, individual fires that burn more than 100,000 acres, are on the rise in the western United States -- the direct result of unintentional yet massive changes weve brought to the forests through a century of misguided management. What steps can we take to avoid further destruction? Forest ecologist Paul Hessburg confronts some tough truths about wildfires and details how we can help restore the natural balance of the landscape.

Why do women who experience sexual assault rarely speak up about it? "Because they fear they wont be believed," says Inés Hercovich. "Because when a woman tells what happened to her, she tells us things we cant imagine, things that disturb us, things we dont expect to hear, things that shock us." In this moving talk, she takes us inside an encounter with sexual assault to give us a clearer idea of what these situations really look like -- and the difficult choices women make to survive. (In Spanish with English subtitles)

From the glorious crested guinea fowl to the adulterous African jacana to vultures that can pick a zebra carcass clean in 30 minutes, Washington Wachira wants us all to get to know the marvelous species of birds that share the planet with us. If youre not already a fan of earths feathermakers -- or concerned about their conservation -- you will be after you watch this delightful talk.

When Gretchen Carlson spoke out about her experience of workplace sexual harassment, it inspired women everywhere to take their power back and tell the world what happened to them. In a remarkable, fierce talk, she tells her story -- and identifies three specific things we can all do to create safer places to work. "We will no longer be underestimated, intimidated or set back," Carlson says. "We will stand up and speak up and have our voices heard. We will be the women we were meant to be."

The most important infrastructure we have is educated minds, says former Tunisian government minister Amel Karboul. Yet too often large investments go to more visible initiatives such as bridges and roads, when its the minds of our children that will really create a brighter future. In this sharp talk, she shares actionable ideas to ensure that every child is in school -- and learning -- within just one generation.

Ever wonder how we poop? Learn about the gut -- the system where digestion (and a whole lot more) happens -- as doctor and author Giulia Enders takes us inside the complex, fascinating science behind it, including its connection to mental health. It turns out, looking closer at something we might shy away from can leave us feeling more fearless and appreciative of ourselves.

"My science fiction has different ancestors -- African ones," says writer Nnedi Okorafor. In between excerpts from her "Binti" series and her novel "Lagoon," Okorafor discusses the inspiration and roots of her work -- and how she opens strange doors through her Afrofuturist writing.

Congratulations! By being here, alive, you are one of historys winners -- the culmination of a success story four billion years in the making. The other 99 percent of species who have ever lived on earth are dead -- killed by fire, flood, asteroids, ice, heat and the cold math of natural selection. How did we get so lucky, and will we continue to win? In this short, funny talk, paleobiologist and TED Fellow Lauren Sallan shares insights on how your ancestors survival through mass extinction made you who you are today.

Could we cure climate change? Geoengineering researcher Tim Kruger wants to try. He shares one promising possibility: using natural gas to generate electricity in a way that takes carbon dioxide out of the air. Learn more -- both the potential and the risks -- about this controversial field that seeks creative, deliberate and large-scale intervention to stop the already catastrophic consequences of our warming planet.

"We all feel a compelling need to watch stories, to tell stories ... to discuss the things that tell each one of us that we are not alone in the world," says TV titan Shonda Rhimes. A dominant force in television since "Greys Anatomy" hit the airwaves, Rhimes discusses the future of media networks, how shes using her narrative-building skills as a force for good, an intriguing concept known as "Amish summers" and much more, in conversation with Cyndi Stivers, director of the TED Residency.

Were building an artificial intelligence-powered dystopia, one click at a time, says techno-sociologist Zeynep Tufekci. In an eye-opening talk, she details how the same algorithms companies like Facebook, Google and Amazon use to get you to click on ads are also used to organize your access to political and social information. And the machines arent even the real threat. What we need to understand is how the powerful might use AI to control us -- and what we can do in response.

Fifty years of armed conflict in Colombia has left the countryside riddled with land mines that maim and kill innocent people who happen across them. To help keep communities safe from harm, TED Resident Carlos Bautista is developing an app to track land mines -- and direct travelers away from them. Learn more about how this potentially life-saving tool could promote peace in countries plagued by land mines once conflicts end.

Machines that can think, learn and adapt are coming -- and that could mean that we humans will end up with significant unemployment. What should we do about it? In a straightforward talk about a controversial idea, futurist Martin Ford makes the case for separating income from traditional work and instituting a universal basic income.

Are diverse companies really more innovative? Rocío Lorenzo and her team surveyed 171 companies to find out -- and the answer was a clear yes. In a talk that will help you build a better, more robust company, Lorenzo dives into the data and explains how your company can start producing fresher, more creative ideas by treating diversity as a competitive advantage.